''On its face, it appears reasonable,'' said Reed Boatright, a spokesman for the National Oceanic and Atmospheric Administration, which oversees the fisheries service.

The death on Aug. 6 was the second this year in the Sea World system of four parks.

It is the park system's eighth killer whale death in the past five years, fisheries records show.

Federal officials said the most recent death does not appear to be related to any of the earlier ones.

''There do not appear to be any overt problems, anything you can point to that's totally awry,'' said Jeannie K. Drevenak, permit officer for the Marine Mammal Commission, an independent agency created by Congress.

The dead animal was named Kenau but, like all adult whales at Sea World, performed under the stage name ''Shamu.''

Her death has left the Sea World system with 12 whales at its four parks. Three of the animals are in Orlando.

The whale was 15 to 16 years old. Sea World officials, citing studies done in Iceland, say that killer whales live 25 to 35 years. Researchers studying wild whales in the Pacific Northwest have found that females may live more than 80 years and males about 50 or 60.

The 12-month old fetus had five months left in its gestation, according to the report.

Animal protectionists, some of whom oppose keeping killer whales in captivity, are withholding comment on the marine park's report until their veterinarians review the studies.

Pneumonia is commonly listed as a cause of death among marine mammals.

The bacteria that caused Kenau's pneumonia is commonly found in healthy and ill marine mammals.

But veterinarians do not know what triggered its rapid spread in the Orlando whale, prompting development of pneumonia.

The huge animals display few signs of illness, said Leslie Dierauf, a veterinarian who specializes in marine mammals.

This seemed like ''a death that could not have been avoided,'' said Dierauf, a staff member on the U.S. House of Representatives Merchant Marine and Fisheries Committee.

She has seen Sea World's report.

Sea World officials have said they were surprised when the animal died.

Except for an infected tooth in late July, the animal had shown no signs of ill health until the day before she died, when she refused to eat.

The illness was not contagious, and none of the other killer whales in the pool had any signs of the disease, said Michael T. Walsh, a Sea World veterinarian who studied the dead animal.

Until independent veterinarians have reviewed the Sea World report - expected to take several weeks - Sea World will delay its importation of a female killer whale now living in England.

On July 31, the fisheries service approved the animal's transfer, but two weeks later asked that the importation be delayed because of the death in Orlando.